ImageFileCollections: Fits file without .fits

[crawfordsm]

If there isn't a '.fits' extension on a file, ImageFileCollections will not pick up the file. The ability to select files without that extension would be a helpful enhancement.

[mwcraig]

@crawfordsm -- did you have in mind checking for a wider range of extensions ('.fit', '.fits', '.fts', ...) or checking each file to see if it is FITS? IIRC, the latter is possible and there may even be a function in astropy for it...

[crawfordsm]

The use case was a fits file without a proper extension. So, I think it would be the former case. It would be useful to explicitly pass it the files that you want to use

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[mwcraig]

If file is given (list of files) it should use those.

[mwcraig]

Could do this by modifying the init to allow for a "check file contents for fits" flag, trying an implementation...